Hi, welcome here.
Well, first double-check your chipset version with
lspci -vnn | grep 14e4:
Output should be device ID 0x4727.
Instead of patching your kernel I'd suggest you upgrade to 3.7.1 Just steal Salckware-current's config file for you arch here: http://mirrors.slackware.com/slackwa...rent/source/k/
along with the source.
Other than that, helpful information can be found here
Furthermore, as brcmsmac/brcmfmac kernel drivers are included in kernels 3.2.29 shipped with Slackware 14 (but not in kernels 2.6.37 shipped with Slackware 13.37) you should be able to use your kernel unmodified, IOW an upgrade is probably not even necessary.
I suspect that the problems comes from the way you configured your network instead. Did you choose NetworkManager when asked by 'netconfig'?